Apparatus for compressing air.



S. G. SKINNER.

APPARATUS 'FOR COMPRESSING AIRA APPLICATION rILBD APR.15,1913.

1,119,889. Patented m1184914.

. 1 M 1 1 @ai 1 4 J7 il UNrrnD STATES 'PATENT OFFICE.

STEPHEN G. SKINNER, OF WILMETTE, ILLINOIS.1

APPARATUS FOR COMPRESSING AIB.

Application filed April 15, 1913.

4 To all whom z't may concern Be it known that I, STEPHEN G. SKINNER, a citizen `of the United States, residing at Vilmette, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Apparatus for Compressing Air, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification. i

My invention relates to apparatus for compressing air and the object of my `invention is to provide a device for that purpose which itself is operated by air compression, so that it may be applied to an otherwise idle cylinder of an internal combustion engine and be operated by the air compressed by the piston in said cylinder.

The device of my invention is particularly adapted for use in the automobile industry, since it may be employed for pumping up tires and may be operated automatically by merely substituting it for one of the spark plugs in an automobile internal combustion engine.

Structurally, the device of my invention comprises a cylinder, preferably of uniform diameter throughout its length, within which is disposed a pair' of connected pistons which are adapted to reciprocate within the cylinder. Located between the two pistons is a chamber, which may be termed the compression chamber. Disposed within this chamber is a stationary piston carried by the wall of the `main cylinder of the pump. A suitable connection which may be screwed into the spark plug opening of an automobile is provided in order that the bottom of the lower piston may be subjected to the compression formedin the enginecylinder. 'The connected pistons are moved intermittently in one direction by the compression formed in the engine cylinder, while the return movement of the pistons is secured by the suction produced by the piston' in the engine cylinder, the air cushion which is formed in the top of the pump cylinder and whatever effect gravity may have( A` valved passage is provided for passing air from below the lower one of the movable pistons to the chamber between the `movable pistons and above the stationary piston therein during `the upward movementof the connected pistons. This `air above the stationary pistonwhose pressure Specication of Letters Patent.

Patented Dec. 8, 19114.

Serial No. 761,276.

has been raised above ordinary air pressure by the engine piston, is adapted to pass around the stationary piston when the movable pump pistons are returned upon the suction stroke of the piston within the engine cylinder. This air is then compounded and forced from the pump upon the next compression stroke of the engine piston. Located in the connection between the pump cylinder and the engine cylinder is a valve which I term the breather valve. This valve is adapted to supply fresh air to the engine cylinder upon the suction stroke of the piston therein. Certain cushioning de` vices areprovided to prevent pounding of the pistons within the pump cylinders.

These and other features of the device of my invention are described in detail in the following description and are illustrated in the accompanying drawings, in which;

Figure 1 is a longitudinal sectional view of the device of my invention, and Fig. 2 is a side elevational view thereof, illustratingr the same in operative position upon the cylinder of an internal combustion engine.

Similar' reference numerals refer to similar parts throughout the several views.

At 3 I have shown the main pump cylinder, within whichis disposed a pair of' reciprocating pistons indicated at 4 and 5 respectively. Ilach of the pistons t and 5 is provided with a suitable piston ring, as shown. Each of the pistons l and 5 is provided withan annular flange, which flanges are illustrated at G and 7 respectively. Having one end threading into each of said flanges is a drawn tube 8 whichrigidly connects the said pistons. The tube 8 is preferably provided with a closed bottom, as shown, in order that it Inav be unnecessary to secure an absolutely, airtight joint between the lower end of the tube and the flange 6 of the piston 4. The upper end of the tube 8, however, is preferably sweated within the flange 7 of the piston 5 in order that the connection therewith may be absolutely airtight.`

The cylinder 3 is provided with a suitable cap 9 and the bottomlO, both'of which are threadedin position, as clearly illustrated. Threa ded'into the cap 9 is a hose connection 11. Threaded into thelower portion of the suitable ball 21, held against said seat by means of a spring 22 carried by a rod 23 threaded into the top of the hose connection .11 and eXtending down through the tube 12. The rod 23 is provided with suitable lugs 24 .for centering the rod 23 within the tube 12 without at the same time in any way preventing the passage of air through the tube 12.

rlhe piston 5 is provided, near the periphery thereof, with a boss 25, which is integral with theI annular iange 7. .The boss 25 is provided with a transverse bore 26 communicating with the inside 'of the drawn tube'S above the piston within said tube, said bore being closed at its outer end by means of a suitable plug 27, as shown. The lower piston 4 is provided with a boss 255 corresponding Yto the boss 25 of the piston 5. The boss 28 is provided with a bore 29, thel inner end oi which communicates with a hollow central boss 30 with which the piston 4 is provided, the outer end of the bore 29 being closed by a suitable plug 30', as shown. Y, y

Extending between the bosses 25 and 28 is a hollow tube 31 which is held in position at either end by means of a solderless airtight joint comprising a tapered brass ring 32 and a nut 33 threaded within itscorresponding boss, which forces said brass ring 32 around the tube 31. I Y

The hollowY central boss 3`Orof the lower piston 4 is provided with a suitable valve seat and a ball normally heldry'sea'ted by means of a spring 34 which acts between said ball and a plug.y 35 threaded into the piston 4, the said spring being preferably disposed around a reduced portion of the' plug, as illustrated. l The bottom 10 is provided with a centrs'nll boss 36 provided with a longitudinal bore therethrough having communication with the inside of the pump cylinder 3. Located within the boss 36 is a breather valve comprising ayalve member 37 normally held seated by means of a spring 38', a`s shown.v Carried by the lower end of the, boss 36 or stem, as it is sometimes called, is a section of pipe 39 adapted to bethreaded into the ordinary spark plug opening of a cylinder of an internal combustion engine. The bot; tom of the pump cylinder-3 is provided with an opening registering with the longitudinal opening through the boss 3G. Near the top thereof the cylinder 3 is providedwith a plurality of apertures 40, the purpose of which will be presently explained.

rlhe operation of the device of my invcntion is as follows: Upon the compression stroke of 'the piston within the engine cylinder with which the device is associated, air passes through the stem into the cylinder 3, below the cylinder 4, air at the same time passing past the valve in the` holl,ow boss 30 of the piston 4 and passing through the hollow tube 31 into the tube 8 above the piston therein. As the connected 'pistons 4 and 5 move upward, due to compression within the engine cylinder, the space vbenwen the bottom of the tubeV 8 and the piston therein becoming less, the air between piston 5 approaches the top of the cylinder 'i n 3, the air between the piston 5 and the top oie the cylinder escapes through the apertures 40 until the piston 5 has passed the apertures, whereupon an air cushion is formed, thus preventing the pistonv 5 from pounding the top of the pump cylinder. Upon the suction stroke of the piston within the engine cylinder purev air at atmospheric pressure is admitted to the engine cylinder through the breather valve in the stem of the device, the connected pistons 4 andl 5 being at the same time moved toward the bottom of the cylinder 3. As thisv operation takes place theV previously compressed air above thel piston in thev tube 8' passes the cup washer 17, thus passing into the lspace between the bottom of the tube 8 and the piston within said tube. Upon the next upward movement' of the' pistons 4 and 5 this air is compounded and passes out of the pump through the tube 12'; As the pis'- ton 4 approaches they bottom of thel cylinder 3, the hollow boss 30' entering the ap'- erture in the bottom of the" cylinder 3 shuts oil? to a large degree communication between the cylinder 3 and the' pump' stein, thus forming an air cushion which prevents the piston 4 from pounding they bottom of the cylinder Y The operation above described may bei continued as long `as ther operation of the piston within the engine cylinder is' continued.

What I claim and desire to secure; by' Let# ers Patent of the United States is:

1. In an', apparatus Vfor compressing air which is adapted to be operated by the alternat'ey suction and compression created within an internal combustion engine cylin# der, the combination with a cylinder adapt; ed to' be connected with the' engine' cylinder,

a piston within said cylinder, a movable compression chamber carried by said piston, a stationary piston for said movable compression chamber, and a valved passage whereby air admitted to said cylinder to operate the movable piston therein is passed to said compression chamber behind the piston therein and thence around said piston upon the next downward movement of said compression chamber.

2. In an apparatus for compressing air which is adapted to be operated by the alternate suction and compression created within an internal combustion engine cylinder, the combination of a pump cylinder adapted to be connected with the engine cylinder, a pair of connected pistons movable within said pump cylinder, a tube connecting said pistons and constituting a compression chamber, a stationary piston within said compression chamber, and a valved passage whereby air admitted to said pump cylinder to operate the connected pistons therein is passed to said compression chamber behind the pistons therein and thence around said piston upon the next movement of said connected pistons impelled by the suction created within the engine cylinder.

3. In an apparatus for compressing air which is adapted to be operated by the alternate suction and compression created within an internal combustion engine cylinder, the combination of a pump cylinder adapted to be connected with the engine cylinder, a movable piston within said pump cylinder, a movable compression chamber carried by said movable piston, a stationary piston for said movable compression charnber, and a passage whereby air admitted to said pump cylinder to operate the piston therein is passed to said compression chamber on the low compression side of the stationary piston therein and thence to the high compression side of said piston upon the next movement of the compression chamber impelled by the suction created within the engine cylinder.

4. Apparatus for compressing air comprising in combination an internal combustion engine cylinder, a pump cylinder of uniform bore, a pair of spaced pistons arranged to be reciprocated within said cylinder, a tube rigidly connecting said pistons, said tube constituting a compression chamber, a stationary piston fixed to the pump cylinder and disposed in said compression chamber, means for establishing connection between the pum cylinder below one of the pistons therein and the internal combustion engine cylinder whereby said connected pistons are reciprocated by the alternate suction and compression created within the engine cylinder, a valved passage through which air admitted to said pump cylinder to operate said pistons is passed to the compression chamber on the low compression side of the stationary piston therein, during a stroke of said connected pistons impelled by the compression created within the associated engine cylinder, said stationary piston comprising a cup-washer whereby air is arranged to pass around said stationary piston when said movable pistons are retracted by the suction created within the engine cylinder.

In witness whereof, I hereunto subscribe my name this 11th day of April A. D., 1913.

STEPHEN G. SKINNER.

Witnesses ALBERT G. MCCALEB, ROBERT F. BRACKE.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of latents, Washington, D. C. 

